showing a message as javascript alert after logout - node.js

Question

app.get('/logout', function (req, res) {
delete req.session.auth;
res.status(200).redirect('/');
});
I am using this for redirecting page after logout. I need to show an alert box when logout is done.Please suggest

Answer 1

This depends on what packages your using. You don't state it so i'll give my two cents with the EJS approach
if you use connect-flash its as simple as :
app.get('/logout', function(req, res) {
delete req.session.auth;
req.flash('message', 'YourMessageHere')
res.redirect('/login');
});
And then when you render it check for the variable like this:
<div>
<%if(message){%>
<%= message%>
<% } %>
</div>
Or you can render the page and pass data along as a json object:
app.get('/logout', function(req, res) {
delete req.session.auth;
res.render('./link/to/html/file', {message: 'Your Message here'});
});
And again in the html check for the variable being passed in.
Look at the res object and see what its capable of and whatever frameworks your using look and see how data can be interpreted.

Answer 2

Maybe you can send a parameter to the redirected page, and, on that page evaluate if the parameter is present or not in order to display the corresponding alert:
app.get('/logout', function (req, res) {
delete req.session.auth;
res.status(200).redirect('/?msg=session%20destroyed');
});
in the '/' logic, you can do something like:
app.get('/', function(req, res) {
var message;
if(req.query.msg){
message = req.query.msg;
}
// other logic here...
res.send(message); // or res.render('index', { msg: message, //other properties...
});
}
You may adapt this depending on the view engine you're using.
Another option, instead of redirecting, send the logout request through ajax, in the server, after destroying the session, response with an 'ok' or '1' status. Then, evaluate the ajax response in order to display the alert in the same page and implement all the corresponding logic on the front (like clearing all forms, displayed info available only when an active session exists, etc).
Express:
app.get('/logout', function (req, res) {
delete req.session.auth;
res.status(200).send('1');
});
In the front (assuming you're using jQuery):
$.get('/logout', function(response){
if(response == '1'){
alert('Successfully logged out!');
// Destroy DOM objects that should not be still available.
}
});
It depends on what's more easy for you to acomplish, the logic in your page and your requirements.